If you want to pique your atheist friends, tell them that their atheism is just a “matter of faith.” They will probably respond that they have the same faith in the non-existence of God as theists have in the non-existence of Santa Claus. So what do atheists mean by the word "faith?"

New atheist Sam Harris writes in his book The End of Faith that “religious faith is simply unjustified belief in matters of ultimate concern.” Other atheists more charitably define faith...

When asked to prove atheism is true, many atheists say that they don’t have to prove anything. They say atheism is not “belief there is no God” but merely “no belief in a God.” Atheism is defined in this context as a “lack of belief” in God, and if Catholics can’t prove God exists, then a person is justified in being an atheist. But the problem with defining atheism as simply “the lack of belief in God” is that there are already another group of people who fall under that definition:...

One of the most interesting and widely discussed arguments for the existence of God is the kalam cosmological argument, which attempts to prove that it is impossible for the universe to have an infinite past. If the argument proves the universe had a beginning, then it follows that some cause that transcends the universe must have brought it into existence. The defender of the kalam argument may also advance other arguments attempting to show that the cause of the universe is God.

One fact that concerns some Christians and elates some atheists is that 93 percent of the members of the National Academy of Sciences, one of the most elite scientific organizations in the United States, do not believe in God. Atheist Sam Harris says that, “This suggests that there are few modes of thinking less congenial to religious faith than science is.”

"Those who belong to God and Jesus Christ ally themselves with the bishop."

~ Ignatius, Saint, Bishop of Antioch, martyr, and disciple of John; writing to the Philadelphians (Philad, iii, 2) circa A.D. 100, insisting on the necessity of unity with the bishop (from the article "Schism").